Has anybody mounted a LP back at the tank to help prime the fuel system after a filter change or pump swap or you get the picture? The last time I did a injector and pump swap it was a real bugger to prime up the system again (had to pressurize the tank with compressed air) and the little manual primer on the stock LP seems useless? I was thinking of using a spare carter I have from the 24v and mounting it the same as the pusher set up on the 24v with a bypass line and a couple of ball valves so I can isolate it when its not use. Any thoughts or ideas?

 

Pressurizing the tank is easier.
If you want to make it even easier do what I did, drill and tap a port in the top of a extra fuel cap to hook the air up to.
I haven't pumped the primer on any 12 valve for well over five years using this method.
Works excellent for finding leaks also.

Another thing to do is install a fuel pressure gauge. This way you don't have to change the filter unless it really needs it. I always make it to at least 30k before the filter needs changing.

 

Thanks Bill
Great idea on the fitting on the extra gas cap I will have to give that a try. What do you put for pressure in there- 10-15psi?

 

10 psi max, don't want to blow up the fuel tank.
Priming it this way the fuel flows from the tank though both the feed and return lines which makes imperative that you open the bleed screw on top of the filter as any air has nowhere to go.
With a fuel tank on the full side this method takes about 15 seconds to fill the filter and purge air.

 

Exellent! Thank you again

 

I'm not sure if anyone else does it this way but I read it here one time to just crack a couple of injector lines and crank the truck over to use the cameshaft lobe on the lift pump to prime everything back up.

Might be hard on the starter but I havn't had any issues with the starter in the many that I have done, but I suppose only time will tell. Usually I stop half way through and let the starter cool down for awhile but when i'm doing my filter changes i'm not usually in a huge hurry, so this wouldn't be the fastest method.

This method can turn extremely messy though if you crank to long and the truck starts firing on three cylinders. Talk about fuel all over the place.

 

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Yeah thats kinda why I was looking for a eazier (on the starter) way of doing it. Filter changes arent so bad its when you pull the lines for injector changes and pump swaps that it seems tougher. Bills tip on the air pressure in the cap will help out alot as I am ussually alone in the shop and last time wrapping a rag around the air line and tring to keep pressure in the tank while cranking it was................... well you get the picture

 

Well if you crack the feed line for the pump and use the rag air/hose method" it should atleast prime up to the IP shouldn't it?

Bill's idea of the fuel cap is a good one though. Simple, fast, effective. Gotta love it.

 

Where exactly is the bleed screw, I don’t remember seeing anything on top of the filter? Shouldn’t the air just go back to the fuel tank via the return line?

About fuel pressure gauges, where is a good point to attach one to, the inlet to the injection pump? I was thinking of using a tapped banjo bolt, like the 24-valves, is this a good way to do it, or is there an easier way? Also where do you guys get your fuel pressure gauges from? The only ones I’ve seen are electric ones that cost over $250, can I use a mechanical fuel pressure gauge used to measure the fuel injection pressure on a gas motor? Thanks.

 

I rigged up a Temp Fuel pressure gauge useing a banjo bolt from a 24v and it seems to work just fine.

 

The bleed screw is on top of the fuel filter, small bolt on top of the outlet to the injection pump banjo bolt. In order to bleed fuel it only needs to be untightened a couple of turns, not totally removed.

Air can't go back to the tank via the return line when the tank is pressurized with air because well, the pressure.

Best way to measure fuel pressure on a 12 valve is remove the injection pump inlet banjo bolt, drill and tap a 1/8" port on top of it. The tapped 24 valve bolts are the wrong size for 12 valve, as far as I know no one sells a tapped banjo for a 12.

Cheaper mechanical fuel pressure gauges are the way to go, the electric ones have a habit of failing.

 

I kept my 24v set-up so I followed suit from that. The only difference was the top of the filter housing wasnt tapped and pipe-plugged like the 24v (the bosses were cast in but not drilled) was so I removed it and drilled and tapped it on the outlet side and reused the SS braided line. I used a Autometer mechanical liquid filled 0-60 Blower gauge since the one I used on the 24v only went to 15psi. The gauge was $50 off ebay (bucky I know) but its a perfect match to my other AM Ultra-Lights.

 

stick a broom or any handle down under your filter and through your brake and electrical lines and pump away within 40 seconds your hear fuel pushing through your IP and start it up

 

gyman98, thats what I do, I personally use a Hoe, gives me something easier to push on, and it is about the right length, but I bet I didn't have 100 strokes to fill the pre and the fuel filter before I heard the overflow singing.

 

ya i would think about 30 strokes is all it takes to make my overflow talk